A spray is a dynamic collection of drops dispersed in a gas. The process of forming a spray is known as atomization. A spray nozzle

Spray nozzle

A spray nozzle is a precision device that facilitates dispersion of liquid into a spray. Nozzles are used for three purposes: to distribute a liquid over an area, to increase liquid surface area, and create impact force on a solid surface...

 is the device used to generate a spray. The two main uses of sprays are to distribute material over a cross-section and to generate liquid surface area. There are thousands of applications in which sprays allow material to be used most efficiently. The spray characteristics

Spray characteristics

Spray nozzles are designed to perform under various operating conditions. The following characteristicsshould be considered when selecting a nozzle:* Spray Pattern* Capacity* Spray impact* Spray Angle* Drop Size- Spray Pattern :...

 required must be understood in order to select the most appropriate technology, optimal device and size.

Fuel sprays

Sprays of hydrocarbon liquids (fossil fuels) are among the most economically significant applications of sprays. Examples include fuel injectors for gasoline and Diesel engines, atomizers for jet engines (gas turbines), atomizers for injecting heavy fuel oil into combustion air in steam boiler injectors, and rocket engine injectors. Drop size is critical because the large surface area of a finely atomized spray enhances fuel evaporation rate. Dispersion of the fuel into the combustion air is critical to maximize the efficiency of these systems and minimize emissions of pollutants (soot

Soot

Soot is a general term that refers to impure carbon particles resulting from the incomplete combustion of a hydrocarbon. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolyzed fuel particles such as cenospheres,...

, NOx

NOx

NOx is a generic term for the mono-nitrogen oxides NO and NO2 . They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures...

, CO).

Electrical Power generation

Limestone slurry is sprayed with single fluid spray nozzles to control acid gas emissions especially sulfur dioxide (SO2) emissions from coal-fired power plants with liquid scrubbers. Calcium hydroxide (lime) is atomized into a spray dryer absorber to remove acid gases (SO2 and HCl) from coal-fired power plants. Water is sprayed to remove particulate solids using a spray tower

Spray tower

Spray towers or spray chambers are a form of pollution control technology. They consist of empty cylindrical vessels made of steel or plastic and nozzles that spray liquid into the vessels. The inlet gas stream usually enters the bottom of the tower and moves upward, while liquid is sprayed...

 or a cyclonic spray scrubber

Cyclonic spray scrubber

Cyclonic spray scrubbers are an air pollution control technology. They use the features of both the dry cyclone and the spray chamber to remove pollutants from gas streams....

  Cooling towers use spray nozzles to distribute water.

Food and beverage

• Sprays are used to wash fruits and vegetables.
• Spray drying is used to produce hundreds of food products, including instant coffee, powdered soups, and flavor concentrates.
• Coating of food products with flavorings and surface additives.
• Cleaning and sanitizing storage tanks, and process equipment single fluid nozzles are used to rinse and wash away materials. These specialized tank-cleaning nozzles often have a fluid powered rotary motion to increase cleaning effectiveness.

Manufacturing

Sprays are used extensively in manufacturing. Some typical applications are applying adhesive, lubricating bearings, and cooling tools in machining operations.

• Cleaning components with sprays of hot water and detergent sprays for degreasing, electric motor rebuilding, diesel engine rebuilding, plant maintenance, steel mill bearings, railroad bearings and engine rebuilding.
• High pressure sprays are used to de-burr machined parts.
• Spray painting
  Spray painting
  Spray painting is a painting technique where a device sprays a coating through the air onto a surface. The most common types employ compressed gas—usually air—to atomize and direct the paint particles. Spray guns evolved from airbrushes, and the two are usually distinguished by their size and the...
  
   is broadly used in many manufacturing processes; for example, for automobiles, appliances, office furniture.

Fire protection

• Spraying water from fixed sprinklers
• High pressure water misting systems for expensive and delicate equipment, for example, marine engine rooms.

Mining

• Water sprays are critical to reducing coal dust during mining*Water is sprayed to control dust emission produced during grinding; spray nozzles are also used for washing gravel in screening plants.

Line & cement

• Suppressing dust from raw materials.
• Feeding fuel to high temperature calcining rotary kilns.
• Cooling and conditioning gas.

Steel industry

• High pressure water is used to remove scale (iron oxide) from red hot steel during the process of rolling into sheet or strip forms.
• Sprays are used in the continuous casing process and quenching of hot gases.
• Quenching coke from coke-ovens
• Cooling metal extrusions
• Picking solutions and rinsing pickling solutions

Chemical, petrochemical, and pharmaceutical

• Spraying reagents to enhance dispersion and to increase liquid-gas mass transfer. Many systems are used, including spray towers.
• Spray drying fluid cracking catalyst for oil refining
• Washing and rinsing solids in filters and centrifuges
• Applying coating to many pharmaceutical tablets

Waste treatment

• Single fluid nozzles are used to break foam in activated sludge wastewater aeration basins and to apply antifoams.
• Water is spray mixed with material being composted.
• Liquid waste is injected into high temperature incinerators.

Agricultural applications

Spray application of herbicides, insecticides, and pesticides is essential to distribute these materials over the intended target surface. Pre-emergent herbicides are sprayed onto soil, but many materials are applied to the plant leaf surface. Agricultural sprays include the spraying of cropland, forest, turf grass, and orchards. The sprayer may be a hand nozzle, on a ground vehicle, or on an aircraft. Herbicides, insecticides and pesticides are spray applied to soil or plant foliage to distribute and disperse these materials. See aerial application

Aerial application

Aerial application, commonly called crop dusting, involves spraying crops with fertilizers, pesticides, and fungicides from an agricultural aircraft. The specific spreading of fertilizer is also known as aerial topdressing....

, pesticide application

Pesticide application

Pesticide application refers to the practical way in which pesticides, are delivered to their biological targets...

, sprayer

Sprayer

A sprayer is a device used to spray a liquid.In agriculture, a sprayer is a piece of equipment that spray nozzles to apply herbicides, pesticides, and fertilizers to agricultural crops...

.
The control of spray characteristics is critical to provide the coverage of foliage and to minimize off target drifting of the spray to adjacent areas. (pesticide drift). Spray drift is managed by applying only in appropriate wind conditions and humidity, and by controlling drop size and drop size distribution. Minimizing the height of the spray boom above the crop reduces drift. The spray nozzle type and size and the operating pressure provide the correct application rate of the material and control the amount of driftable fines.
Spays, single fluid nozzles, are also used to cool animals

Consumer products

Atomizers are used with pump-operated sprays of household cleaning products. The function of these nozzles is to distribute the product over an area. see Aerosol spray

Aerosol spray

Aerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles. This is used with a can or bottle that contains a liquid under pressure. When the container's valve is opened, the liquid is forced out of a small hole and emerges as an aerosol or mist...

 and spray can

• Water and detergent sprays for the car washing